import java.util.ArrayList;
import java.util.List;

public class Test {
    public static void func(String str1,String str2){
        List<Character> ret = new ArrayList<>();
        for (int i = 0; i < str1.length(); i++) {
            char ch = str1.charAt(i);
            if (!str2.contains(ch + "")) {
                ret.add(ch);
            }
        }
        for (int j = 0; j < ret.size(); j++) {
            System.out.print(ret.get(j)+",");
        }
        System.out.println( "    ");
    }


    public static void main(String[] args) {
        /*ArrayList<Integer> arraylist = new ArrayList<>();
        List<String> list = new ArrayList<>();*/
        String str1 = "welcom to bit";
        String str2 = "come";
        func(str1,str2);
    }
}
